Cummins ISB6.7 G engine enters production

The Cummins Westport ISB6.7 G engine, first presented at the 2015 ACT Expo in Dallas, Texas, has recently hit the assembly line, having completed a string of tests. The unit is intended for commercial vehicles, including medium-duty buses.

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Cummins Westport Inc. (CWI) announced that production of the ISB6.7 G unit has commenced. The 6,7-litre engine can run on any kind of natural gas – compressed, liquefied or biomethane. It's based on the ISB6.7 Diesel engine and it's CWI's methane-powered unit to receive EPA and CARB emission certifications in the US as far as Low NOX standards are concerned. NOX emissions of the ISB6.7 G unit are by 50% below the EPA and CARB required limits, while CO2 and GHG emissions are EPA 2017-compliant. All CWI's gas engines comply with the EPA 2010 standard when it comes to particulate matter emissions.

An engine of this size is a natural addition to CWI’s portfolio of natural gas engines. Many customers using school and shuttle buses, medium duty trucks, or vocational vehicles operate within a local area where the return to base nature of their operation allows them to use fleet-owned or growing publicly available natural gas fueling infrastructure. The ISB6.7 G offers the midrange customer an ability to take advantage of the most cost-effective overall solution with the benefit of a low emission natural gas engine that has proven performance, reliability, and durability.

The ISB6.7 G runs on a stoichiometric air-fuel mixture and uses a cooled exhaust gas recirculation system (SEGR). The crank case deaerating system is a closed-circuit one to cut emissions and exhaust gasses are treated by a maintenance-free three-way catalytic converter. The unit requires no particulate filter or selective catalytic reduction technology utilising AdBlue (32,5% urea solution).

The engine is offered in three output variants – 200, 220 and 240 PS. It can be optionally equipped with a PTO and mated to automatic transmission. Development of the ISB6.7 G was financed with funds from the California Energy Commission (Public Interest Energy Research program) and the Gas Technology Institute. The engine is covered by 2-year unlimited mileage warranty.